"High x Alpha" is most versatile tunes.
(Power; +2 STR -1 TEC, +10 COST)
(Tech; +2 TEC, -1 STR, +10 COST)
(Run; +2 WLK, -1 FLY, +10 COST)
(Boost; +2 FLY, -1 WLK, +10 COST)
(Tough; +2 TGH, -1 FLY, +10 COST) (Least recommended)
Mixing "High x Beta" with "High y Beta" tends to do good, but is more complicated.
EX:
High Boost Beta (+2 FLY, -1 WLK, -1 STR, +5 COST)
+
High Tech Beta (+2 TEC, -1 STR, -1 FLY, +5 COST)
=
-2 STR, +2 TEC, -1 WLK, +1 FLY, +10 COST
Effective for FLYARTs and Generic AIRs if you're throwing STR in the negatives.
If you have many slots but not alot of capa, use generic "x" tunes.
(Power; +1 STR +5 COST)
(Tech; +1 TEC, +5 COST)
(Run; +1 WLK, +5 COST)
(Boost; +1 FLY, +5 COST)
(Tough; +1 TGH, +5 COST)
Avoid "Great x y" tunes unless you have little slots but alot of capa.
Always have at least 1 WLK or 1 FLY. To me, I'd keep 3 WLK or 3 FLY. But that's just me.
Life tunes got buffed recently. Life is where you should use Proto Cosmos on.
(Proto Life; +15 HP, +5 COST)
(Life; +15 HP, +10 COST)
Avoid combination tunes unless they're the ones that increase HP and a generic stats. Those tunes are effectively a generic tune and a regular life mixed together.
(Beast; +15 HP, +1 STR, +15 COST)
(Range; +15 HP, +1 TEC, +15 COST)
(Tank; +15 HP, +1 WLK, +15 COST)
(Eagle; +15 HP, +1 FLY, +15 COST)
(Sentinel; +15 HP, +1 TGH, +15 COST) (Most recommended)
I don't know much myself. Await for Trill or Suguri or someone to post.